This application is for a 5-year extension of funding for the Pediatric Eye Disease Investigator Group (PEDIG) Coordinating Center (CC). Since its inception in 1997, PEDIG has conducted 4 protocols in strabismus, 19 protocols in amblyopia, 3 protocols in nasolacrimal duct obstruction, 2 protocols in myopia/hyperopia, & several pilot studies. By the time the funding requested in this application would begin, it is expected that 3 new protocols will have started: a randomized trial to evaluate treatment for convergence insufficiency, a randomized trial to compare botulinum toxin with incisional surgery for esotropia, and a clinical disease registry to evaluate uveitis incidence in children with juvenile idiopathic arthritis. Despite these accomplishments, many important questions and controversies remain in pediatric eye care and strabismus. PEDIG has developed, or will be developing, clinical trials to address many of these questions. These include (1) treatment strategies for children with a visual deficit despite maximal amblyopia treatment, (2) the effect of prescribing versus not prescribing spectacles for hyperopia in young children, (3) the best surgical and non-surgical treatments for intermittent exotropia, (4) risk factors for complications after cataract surgery, ad (5) the optimal treatment for convergence insufficiency. Specific aims for the next 5-year funding period for PEDIG are to: (1) complete the 7 protocols that are expected to be in progress at the time the funding period begins, (2) initiate 10 new protocols in common pediatric eye disorders where the current management does not have a proven rationale, (3) continue to expand the PEDIG network by soliciting the participation of new sites and encouraging the involvement of young investigators, (4) continue to educate pediatric ophthalmologists, pediatric optometrists, and clinical research coordinators on the principles of clinical trials and good research practices (5) train pediatric ophthalmologists and pediatric optometrists to be leaders in clinical trials an clinical research, and (6) develop new methods and outcome measures needed to conduct future amblyopia and strabismus trials as described in the parallel MCPDOC grant proposal. The Coordinating Center plays a key role in the Network's ability to achieve these goals.